What kind of oil should be used in a vacuum pump?
4 Answers
Vacuum pump oil should be used. Vacuum pump oil is a special lubricant specifically developed for vacuum pumps on vacuum equipment, and it is divided into two types: mineral oil and synthetic oil. The following are the performance characteristics of vacuum pump oil: 1. Stability: Vacuum pump oil has excellent oxidation stability. Even when exposed to air, resin, chemical raw materials, etc., under high-temperature conditions for a long time, it is not easy to deteriorate, reducing the formation of harmful paint films and oil sludge and providing a longer oil change interval. 2. Anti-corrosion: Vacuum pump oil has outstanding rust and corrosion resistance, forming a highly effective anti-corrosion film on metal surfaces, thereby comprehensively preventing system corrosion caused by inhaling corrosive gases and moisture.
I recently researched vacuum pump oil changes. For the vacuum booster pump in cars, it's recommended to use dedicated vacuum pump oil—never use engine oil! This oil must withstand high temperatures and have low evaporation rates, otherwise oil mist in the intake pipes can cause brake failure. Older vehicles can use No. 22 or 32 vacuum pump oil, but newer cars with start-stop systems require low-viscosity synthetic oil. Don't exceed 20,000 km between oil changes—replace it if the oil turns black. Last time I saw someone cheap out and use transmission fluid, resulting in pump carbon buildup and complete failure. When buying oil, look for the DIN V 51519 standard—it's the right choice.
With twenty years of car repair experience, I know there's a lot to pay attention to when it comes to vacuum pump oil. Mechanical vacuum pumps must use mineral-based vacuum pump oil, with a viscosity grade of ISO VG 32. The oil filling point is at the oil filler hole on the side of the pump body, and it's just right to fill it up to 3/4 of the sight glass. I've encountered cases where customers mistakenly added brake fluid—the rubber components of the vacuum pump all swelled up. A reminder: when evacuating, don't unscrew the oil filler hole screw, as it may spray out high-temperature oil. After changing the oil, remember to start the engine and pump the brakes a dozen times to ensure the new oil fully lubricates the pistons.
Many modern vehicles don't even require vacuum pump oil changes! Electronic vacuum pumps have no oil circuit design, so maintenance manuals omit this item. For mechanical pumps, choose oil based on three criteria: ash content below 0.1%, flash point exceeding 220°C, and viscosity index above 95. During maintenance, ensure there are no metal particles in the oil. Last week, a Lexus was repaired precisely because counterfeit oil purchased from an auto parts market caused vacuum valve sticking. Professional shops use fully synthetic oils like Germany's Klüber V50-722 – though expensive, it lasts for 60,000 kilometers.
